module nazo.md5;
/**
 * FastMd5 based on std.md5
 */

/* Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
rights reserved.

License to copy and use this software is granted provided that it
is identified as the "RSA Data Security, Inc. MD5 Message-Digest
Algorithm" in all material mentioning or referencing this software
or this function.

License is also granted to make and use derivative works provided
that such works are identified as "derived from the RSA Data
Security, Inc. MD5 Message-Digest Algorithm" in all material
mentioning or referencing the derived work.

RSA Data Security, Inc. makes no representations concerning either
the merchantability of this software or the suitability of this
software for any particular purpose. It is provided "as is"
without express or implied warranty of any kind.
These notices must be retained in any copies of any part of this
documentation and/or software.
 */

import std.string, nazo.mem, std.stdio;

/***************************************
 * Computes MD5 digest of array of data.
 */

/******************
 * Prints a message digest in hexadecimal to stdout.
 */
void printDigest(ubyte digest[16])
{
    foreach (ubyte u; digest)
        printf("%02x", u);
}

/****************************************
 * Converts MD5 digest to a string.
 */

char[] digestToString(ubyte[16] digest)
{
    char[] result = new char[32];
    int i;

    foreach (inout ubyte u; digest)
    {
        result[i++] = std.string.hexdigits[u >> 4];
        result[i++] = std.string.hexdigits[u & 15];
    }
    return result;
}

    /* ROTATE_LEFT rotates x left n bits.
     */
    static uint ROTATE_LEFT(uint x, uint n)
    {
        version (X86)
        {
            asm
            {   naked                        ;
                mov        ECX,EAX                ;
                mov        EAX,4[ESP]        ;
                rol        EAX,CL                ;
                ret        4                ;
            }
        }
        else
        {
            return (x << n) | (x >> (32-n));
        }
    }

    /* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
     * Rotation is separate from addition to prevent recomputation.
     */
    /* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
     * Rotation is separate from addition to prevent recomputation.
     */
    static void FF(inout uint a, uint b, uint c, uint d, uint x, uint s, uint ac)
    {
        a += ((b & c) | (~b & d)) + x + cast(uint)(ac);
        a = ROTATE_LEFT (a, s);
        a += b;
    }

    static void GG(inout uint a, uint b, uint c, uint d, uint x, uint s, uint ac)
    {
        a += ((b & d) | (c & ~d)) + x + cast(uint)(ac);
        a = ROTATE_LEFT (a, s);
        a += b;
    }

    static void HH(inout uint a, uint b, uint c, uint d, uint x, uint s, uint ac)
    {
        a += (b ^ c ^ d) + x + cast(uint)(ac);
        a = ROTATE_LEFT (a, s);
        a += b;
    }

    static void II(inout uint a, uint b, uint c, uint d, uint x, uint s, uint ac)
    {
        a += (c ^ (b | ~d)) + x + cast(uint)(ac);
        a = ROTATE_LEFT (a, s);
        a += b;
    }

    void sum(ubyte[16] digest, const(ubyte)[] input)
    {
      ubyte[64] last;
      uint* tmp = cast(uint*)digest.ptr;
      *tmp++=0x67452301;
      *tmp++=0xefcdab89;
      *tmp++=0x98badcfe;
      *tmp  =0x10325476;

      ulong count = input.length << 3;//*8
      uint cur=input.length & 0b111111;//%64
      if(cur){
        last[0..cur] = input[$-cur..$];
        input.length=input.length - cur;
      }
      last[cur++]=0x80;

      for (uint i = 0; i < input.length; i += 64)
        transform (cast(uint*)(input.ptr+i), cast(uint*)digest.ptr);

      if(cur+8 > 64){
        transform (cast(uint*)last.ptr, cast(uint*)digest.ptr);
        memzero!(64-8)(last.ptr);
      }
      memcpy!(8)(last.ptr+(64-8) ,&count);
      transform (cast(uint*)last.ptr, cast(uint*)digest.ptr);
    }

    void sum(ubyte[16] digest, ubyte* input64, const(ubyte)[] input)
    {
      ubyte[64] last;
      uint* tmp = cast(uint*)digest.ptr;
      *tmp++=0x67452301;
      *tmp++=0xefcdab89;
      *tmp++=0x98badcfe;
      *tmp  =0x10325476;

      ulong count = (input.length+64) << 3;//*8
      uint cur=input.length & 0b111111;//%64
      if(cur){
        last[0..cur] = input[$-cur..$];
        input.length=input.length - cur;
      }
      last[cur++]=0x80;

      transform (cast(uint*)input64, cast(uint*)digest.ptr);

      for (uint i = 0; i < input.length; i += 64)
        transform (cast(uint*)(input.ptr+i), cast(uint*)digest.ptr);

      if(cur+8 > 64){
        transform (cast(uint*)last.ptr, cast(uint*)digest.ptr);
        memzero!(64-8)(last.ptr);
      }
      memcpy!(8)(last.ptr+(64-8) ,&count);
      transform (cast(uint*)last.ptr, cast(uint*)digest.ptr);
    }

    /* MD5 basic transformation. Transforms state based on block.
     */

    /* Constants for MD5Transform routine. */
    enum
    {
        S11 = 7,
        S12 = 12,
        S13 = 17,
        S14 = 22,
        S21 = 5,
        S22 = 9,
        S23 = 14,
        S24 = 20,
        S31 = 4,
        S32 = 11,
        S33 = 16,
        S34 = 23,
        S41 = 6,
        S42 = 10,
        S43 = 15,
        S44 = 21,
    }

    private static void transform (uint* x, uint* digest)
    {
      uint a = digest[0],
           b = digest[1],
           c = digest[2],
           d = digest[3];

      /* Round 1 */
      FF (a, b, c, d, x[0], S11, 0xd76aa478); /* 1 */
      FF (d, a, b, c, x[1], S12, 0xe8c7b756); /* 2 */
      FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
      FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
      FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
      FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
      FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
      FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
      FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
      FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
      FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
      FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
      FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
      FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
      FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
      FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

     /* Round 2 */
      GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
      GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
      GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
      GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
      GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
      GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
      GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
      GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
      GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
      GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
      GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
      GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
      GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
      GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
      GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
      GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

      /* Round 3 */
      HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
      HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
      HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
      HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
      HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
      HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
      HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
      HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
      HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
      HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
      HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
      HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
      HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
      HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
      HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
      HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

      /* Round 4 */
      II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
      II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
      II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
      II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
      II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
      II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
      II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
      II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
      II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
      II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
      II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
      II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
      II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
      II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
      II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
      II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

      digest[0] += a;
      digest[1] += b;
      digest[2] += c;
      digest[3] += d;
    }

unittest
{
    debug(md5) printf("std.md5.unittest\n");

    ubyte[16] digest;

    sum (digest, cast(ubyte[])"");
    assert(digest == cast(ubyte[])x"d41d8cd98f00b204e9800998ecf8427e");

    sum (digest, cast(ubyte[])"a");
    assert(digest == cast(ubyte[])x"0cc175b9c0f1b6a831c399e269772661");

    sum (digest, cast(ubyte[])"abc");
    assert(digest == cast(ubyte[])x"900150983cd24fb0d6963f7d28e17f72");

    sum (digest, cast(ubyte[])"message digest");
    assert(digest == cast(ubyte[])x"f96b697d7cb7938d525a2f31aaf161d0");

    sum (digest, cast(ubyte[])"abcdefghijklmnopqrstuvwxyz");
    assert(digest == cast(ubyte[])x"c3fcd3d76192e4007dfb496cca67e13b");

    sum (digest, cast(ubyte[])"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789");
    assert(digest == cast(ubyte[])x"d174ab98d277d9f5a5611c2c9f419d9f");

    sum (digest, cast(ubyte[])
        "1234567890123456789012345678901234567890"
        "1234567890123456789012345678901234567890");
    assert(digest == cast(ubyte[])x"57edf4a22be3c955ac49da2e2107b67a");

    assert(digestToString(cast(ubyte[16])x"c3fcd3d76192e4007dfb496cca67e13b")
        == "C3FCD3D76192E4007DFB496CCA67E13B");
}
